Digestive System
You eat when you get hungry.
It seems so simple. You take a bite out of a sandwich.
That bite then begins
an amazing journey. That bite goes through every part of your digestive system.
Your body digests, or breaks down, the food into smaller and smaller parts. At
the end of the journey your blood carries chemicals from your sandwich to every
part of your body.
WHAT
IS YOUR DIGESTIVE SYSTEM LIKE?
Your digestive system
is one long, winding tube. The digestive system of a grown-up is 20 to 30 feet
(6 to 9 meters) long.
Food goes from your mouth
to your throat. It then slides down a tube called the esophagus. It drops into
your stomach. From there it gets squeezed into your small and large intestines.
WHERE
DOES DIGESTION START?
You start to digest food
in your mouth. You bite off a piece of sandwich. Your teeth grind the bite up.
Your mouth waters with a liquid called saliva. Saliva helps make the bite of
chewed-up sandwich soft and wet.
After you chew up the
bite of sandwich, you swallow it. Your tongue pushes the chewed-up food into
your esophagus. Your esophagus is like a chute that sends the food into your
stomach.
WHAT
HAPPENS IN YOUR STOMACH?
Your stomach breaks down
the food even more. Your stomach is like a bag made of muscles. Liquids called
digestive juices pour into your stomach. Your stomach muscles churn the food
around to mix it with the juices. The juices break down the food. The food
turns into a liquid in your stomach.
That bite of sandwich
does not look like bread, lettuce, cheese, or meat anymore. It is broken down
into chemicals called fats, proteins, starches, and sugars.
It takes your stomach
about four hours to do its job. Your stomach then sends the liquefied food on
to your small intestine. You start to feel hungry again when your stomach is
empty. Sometimes your stomach muscles start to churn when your stomach is
empty. When this happens, you can hear your stomach growl.
WHAT
HAPPENS IN YOUR SMALL INTESTINE?
The job of digesting your
sandwich gets finished in your small intestine. Your small intestine is a long
and narrow, twisty tube. The small intestine is by far the longest part of the
digestive system. Muscles surrounding this tube push the liquid along. More
juices break the food down even further.
Eventually the food is
broken down into chemicals that your body can use. These chemicals go through
the wall of your small intestine. They go into tiny blood vessels just outside
the wall. Your blood picks up the chemicals. Your blood carries them to every
part of your body. The food chemicals go from your blood into your cells. Your
cells use the chemicals to make the energy you need to do your homework, run, and
play.
Other organs around your
small intestine help it digest food. Your liver and gallbladder help digest
fats in foods. Your liver also helps your body store extra food that it cannot
use right away. Your pancreas creates the chemical insulin. Insulin helps your
body use sugar.
There are some leftovers
that get to the end of your small intestine. The leftovers go into your large
intestine.
WHAT
HAPPENS IN YOUR LARGE INTESTINE?
Your large intestine is
shorter and thicker than your small intestine. Your large intestine takes water
out of the leftovers. It also takes out some vitamins and minerals.
Bacteria that live in
your large intestine break down any leftover food. Bacteria are tiny living
things that you can only see with a microscope. What is left in your large
intestine is solid waste.
Muscles in your large
intestine push the waste along. It goes from your colon to your rectum. The
waste gets pushed out of your body through an opening called the anus.
